1. Technical Field
The present invention relates to a photoelectric conversion element, a method for manufacturing the same, an optical sensor, and a solar cell.
2. Related Art
In the related art, a photoelectric conversion element which converts light energy into electrical energy has been widely used in an illuminometer as a photodiode photodetector, a camera exposure meter, an auto strobe optical sensor, a smoke sensor, an optical remote controller, a position measuring sensor, or the like.
As a product using the principle of a photodiode, a solar cell capable of reducing a load to the environment has drawn attention. As a solar cell, a solar cell using silicon as a photoelectric conversion material is widely known (for example, refer to JP-A-53-33084) and is substantially divided into three types of single crystalline type, polycrystalline type, and amorphous type, each of which has been put into practical use.
Study of a next-generation solar cell has become popular and a wet type dye sensitized solar cell in which an electrolyte is charged between an anode electrode and a cathode electrode is proposed (for example, refer to JP-A-1-220380). Further, a photoelectric conversion element including a transparent electrode formed of an n-type oxide semiconductor as a light receiving side electrode, in which a p-type semiconductor layer having the energy difference between a Fermi level and the lower limit of a conduction band that is larger than the energy difference between a Fermi level and the lower limit of a conduction band in the p-type semiconductor layer is further joined between the transparent electrode and the p-type semiconductor layer, is proposed (for example, refer to JP-A-2012-38783).
In addition, a photoelectric conversion structure including a film structure formed of a photovoltaic material, and a positive electrode and a negative electrode, in which the film structure is a structure in which an orientation control layer is laminated or a dielectric layer is laminated on the upper part of the orientation control layer, is proposed (for example, refer to JP-A-2006-93385).
However, for the silicon-based solar cell as described in JP-A-53-33084, a high manufacturing cost is incurred and the manufacturing conditions have to be strictly controlled, and further, a large amount of energy is required in the manufacturing. Thus, there is still room for examination from the viewpoint of energy saving and mass productivity.
In the dye sensitized solar cell as described in JP-A-1-220380, the electrolyte is evaporated after long-term use and thus the electrode performance is lowered.
In the photoelectric conversion element as described in JP-A-2012-38783, it is necessary to provide a predetermined p-type transparent semiconductor layer to be interposed between the n-type oxide semiconductor and the p-type semiconductor layer or to set the energy levels of the p-type transparent semiconductor layer and the p-type semiconductor layer to have a predetermined relationship. Thus, the configuration and the manufacturing process easily become complicated and the configuration is disadvantageous from the viewpoint of simplicity and mass productivity.
Further, the photoelectric conversion structure described in JP-A-2006-93385 utilizes the ferroelectric properties of the dielectric layer, but in a photoelectric conversion apparatus using such a principle, the photoelectric conversion efficiency is easily reduced and a large photoelectric current is not easily obtained. Further, depending on the dielectric material, it is necessary to carry out a polarization treatment in which polarization voltage for voluntarily aligning the electric dipole moment is applied and thus, the configuration is also disadvantageous from the viewpoint of simplicity and mass productivity.